April 5, 2009
A.R.
Big Idea: Negative numbers help us model many real world situations
Essential Q: How do I add integers?
Notes: Black circle: +1 Red Circle: -1

A. Use chipboard and black and red chips to find each sum. Draw a series of chipboards to illustrate your work.

1. –8 + -7
2. –8 + +7
3. +8 + -7
4. +8 + +7

ARchipboard2.2.gif

B. Find the two combinations of black and red chips that will simplify to represent the given integer. Draw a series of chipboards to prove that each combination works.

  1. -3

andrewrchipboard2.gif

Problem 2.2 Follow Up:

1. What integer added to –8 gives the sum of –4?
You have to add 4 to –8 and that gives the sum of-4.

2. Give two integers with the sum that is less than either of the two integers.
-10 + 9 = -1
-32 + 8 = -23

3. Give two integers with the sum that is greater then either two of the integers.
-39 - 7 = -46
-10 + 9 = -19